丙烯/1-丁烯聚合物合金的单体组成切换法制备:动力学及聚合器模型

采用球形负载型Ziegler-Natta催化剂和单体组成周期性切换的丙丁淤浆共聚合技术,原位制备了聚丙烯/丙丁共聚物合金。将共聚动力学的矩模型与物料衡算相结合,首次建立了单体组成切换的共聚反应器模型。依据实验所得的丙烯实时消耗速率拟合得到模型参数,并模拟计算了不同单体组成切换频率下的聚合反应活性和聚合产物的组成。结果表明,模型能很好地描述各切换频率下丙烯的聚合速率曲线、催化聚合活性,以及合金中1-丁烯的总含量、丙丁无规共聚物的含量和"嵌段"共聚物的含量等。结果还显示,共聚过程中丙烯的脉冲进料有利于提高单体向活性中心的扩散,进而提高聚合速率和聚合活性。     

单体组成切换法调控聚丙烯/丁烯合金的结构与性能

为解决聚丙烯材料抗冲击强度低的问题,同时利用国内大量廉价的1-丁烯资源,采用单体组成切换法在反应器内进行丙烯本体均聚和丙烯/丁烯本体共聚,原位制备聚丙烯合金。该合金主要由丙丁无规共聚物、长丙烯链段的丙丁嵌段共聚物和高等规度的聚丙烯组成。共聚物作为橡胶相分散在聚丙烯基体中,形成海岛结构,充当应力集中点,起到诱发及终止银纹、吸收能量的作用。长丙烯链段的嵌段共聚物增加了橡胶相与基体的相容性,使合金材料具有优异的刚性和韧性平衡,材料的抗冲击强度最高达48.91 kJ/m²。本文探究了聚合工艺对合金组成结构的影响,并揭示了合金组成结构和相形态、力学性能的关系。     

聚1-丁烯与少量丙烯釜内合金的合成与表征

采用自制的负载钛催化体系[TiCl4／MgCl2-AlEt3],合成了聚1-丁烯与少量丙烯的釜内合金。考察了反应温度、反应时间、催化剂加入量、丙烯与1-丁烯共聚时间等肘催化活性和合金等规度的影响。从而确定了该材料的最佳生产条件。实验结果表明Ti／Bt值约为2．2×10^-5,Al／Ti为200左右时,催化剂的催化活性相对较高。升高温度和延长反应时间同样可以提高催化活性及增大合金中的丙烯单元含量。同时还对合金进行了结构表征。     

负载钛催化1-丁烯聚合动力学

采用TiC l4/MgC l2-A l(i-Bu)3催化剂合成聚1-丁烯热塑性弹性体,研究了不同单体浓度、催化剂浓度和反应温度下及催化剂陈化后的聚合动力学。结果表明,聚合初期聚合速率与单体浓度和催化剂浓度的一次方成正比,在20~40℃,聚合的表观活化能为14 kJ/mol,聚合的速率方程为Rp=kp[Ti][B t];0℃陈化催化剂的1-丁烯聚合速率较非陈化时快。     

丙烯/1-丁烯无规共聚树脂等温结晶动力学研究

采用本体聚合方法合成了丙烯/1-丁烯无规共聚树脂,通过DSC研究了丙烯/1-丁烯无规共聚物的等温结晶动力学。根据Avrami方程求出了各个结晶温度下的结晶动力学参数K(T)、 n、t1/2,以及样品的结晶活化能。结果表明,随着结晶温度的升高,同一样品的结晶速率逐渐下降,说明样品的结晶是依热成核控制为主;Avrami指数 在3~4之间,表明共聚物晶体的生长方式为三维球状生长。在同一结晶温度条件下,随着共聚物中1-丁烯单元含量的增加,晶体的成核和结晶速率均下降,结晶活化能增加,共聚物中1-丁烯单元含量对结晶速率的影响很大。     

负载钛催化1-丁烯本体聚合动力学

采用TiCl4/MgCl2-Al(i-Bu)3催化体系在10 L聚合釜中研究了本体法1-丁烯的聚合动力学.结果表明,在反应温度为20 ℃的条件下,聚合的速率方程为Rp=157[Ti]1.1[Bt]PH20.4;在10～30 ℃时的聚合活化能为46 kJ/mol.提高催化剂浓度、聚合温度和氢气压力均能明显提高单体转化率,加快聚合速率.     

聚氨酯/环氧树脂互穿网络聚合物反应动力学

通过共混法制备了聚氨酯(PU)/环氧树脂(EP)互穿网络聚合物(IPN),采用示差扫描量热法(DSC)和动态机械分析(DMA)对IPN形成过程中的固化反应动力学及产物IPN的相容性进行了研究,结果表明,m(PU)/m(EP)=10∶6的IPN体系的反应级数为0.95,表观活化能为169.23 kJ/mol;PU/EP IPN只有1个玻璃化转变温度,相容性好。     

1-丁烯与H2S反应制备仲丁硫醇动力学研究

以Al2O3为载体,采用等体积浸渍法制备了P2O5-MoO3/Al2O3催化剂。在排除内外扩散影响的条件下,研究了1-丁烯与H2S在P2O5-MoO3/Al2O3催化剂上反应生成仲丁硫醇反应的本征动力学。在反应温度120~180℃、压力0.2 MPa的条件下,考察了反应温度、1-丁烯分压和硫化氢分压对反应速率的影响。对1-丁烯在P2O5-MoO3/Al2O3催化剂上的催化硫化机理进行了探讨。实验结果表明,1-丁烯与H2S在P2O5-MoO3/Al2O3催化剂上的反应机制是1-丁烯与H2S发生共吸附后由表面反应控制的二级催化反应,根据该机理得到反应动力学方程为A B2A A B B A(1)kp p r K p K p根据实验数据得到其指前因子k0=3.3×109,活化能Ea=60.78 kJ/mol。     

响应面法优化制备戊烯/辛烯/十二烯共聚物减阻剂

采用溶液聚合法,选用Ziegler-Natta催化剂,将1-戊烯作为单体之一,合成了1-戊烯/1-辛烯/1-十二烯三元共聚物减阻剂,通过核磁共振仪（¹³C NMR）、傅里叶变换红外光谱计（FT-IR）、X射线衍射（XRD）对聚合物的结构与性质进行了表征,并采用室内环道装置评价了聚合物的减阻性能。采用响应面分析法通过建立减阻率与各因素之间的Box-Behnken数学模型,对三元共聚工艺进行优化,最优聚合条件为：戊烯量0.07 ml,十二烯：辛烯=4,主催化剂量0.07 g,助催化剂量0.4 ml,在此条件下得到的三元共聚物在添加量10×10^-6时减阻率为59.79%。在实验选取的添加量范围内,各因素对减阻率影响显著性顺序为：戊烯添加量 >助催化剂用量 >主催化剂用量 >十二烯：辛烯;各因素之间的交互作用也显著存在。引入戊烯制备所得的减阻剂结晶度下降,溶解效果明显优于1-辛烯/1-十二烯二元共聚物,减阻率得到了提高。     

Extracting kinetic parameters of aniline polymerization from thermal data of a batch reactor. simulation of the thermal behavior of a reactor

A simulation model of the thermal behavior of a reactor during aniline polymerization is proposed. The model takes into account the polymerization mechanism together with heat production and dissipation. The temperature–time profiles can be simulated with different kinetic parameters. The model is used for two purposes: to extract kinetic parameters by fitting experimental temperature–time profiles of a cooled agitated batch reactor; and to estimate the temperatures changes occurring in a reactor under different experimental conditions to find the best conditions for industrial production of polyaniline. The rate equation used includes two rate constants: one in the absence of polymer (k₁) and another in the presence of polymer (k₂). The thermal factors, such as the heat transfer coefficient and the reaction enthalpy, are experimentally measured. A computer program is written that fits the experimental data using different kinetic parameters. The data analysis shows a temperature peak (T_max) whose magnitude decreases when k₂ decreases, whereas it is not affected by k₁. The time to reach the T_max is inversely proportional to k₁ and k₂. The model allows obtaining the kinetic parameters in different reaction media, e.g. varying the concentration of acid. The model is used to simulate the thermal behavior, to polymerize 1M of aniline: in one step the temperature of the reactor will increase till 82ºC, such thermal runaway will cause polymer degradation, successive additions of portions of the total oxidant amount, paced at defined time intervals, is devised to maintain low temperatures while producing the same amount of polymer. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39409.     

A dynamic analysis of chalcopyrite bioleaching in continuous flow reactor systems

A dynamic analysis of chalcopyrite bioleaching was performed in continuous flow systems. In contrast to a previous batch analysis¹ in which the influence of particle surface area on reaction rate was not accounted for, the unsteady‐state change in particle surface area was integrated into the dynamic analysis by application of the modified PBM.² The current study extends the analysis to include the influence of convective flow on the system. It is demonstrated that the analysis can be used to determine feasible control strategies for operating near the steady‐state maximum rate that is stable. Two strategies were evaluated for the purpose of increasing the leaching rates, showing that an increased rate of 56% is feasible. Analysis on experimental data showed that increased rates can be achieved by controlling the biomass concentration and ferric:ferrous ion ratio at an optimum by increasing the solids loading [m/v] in the reactor. © 2011 American Institute of Chemical Engineers AIChE J, 58: 2428–2440, 2012     

Dehydrogenation kinetic model of heavy paraffins

Based on the dehydrogenation mechanism of heavy paraffins under industrial conditions, the intrinsic reaction kinetic model and catalyst deactivation model were established considering the influence of side reactions with different carbon‐number heavy paraffins. Based on the experimental data of dehydrogenation reactions with different carbon‐number paraffins in an axial continuous‐flow isothermal fixed‐bed microreactor, Powell optimization method was used to estimate the model parameters. The results show that there is a liner relationship between the activation energies and pre‐exponential factors of homologous reactions and carbon number of paraffins. A correlation model about the deactivation rate constants under different conditions was established. The validation of kinetic model showed that the model could be used to predict detailed product distribution with different feedstocks under different reaction conditions. © 2017 American Institute of Chemical Engineers AIChE J, 2017     

茂金属催化 1-丁烯聚合反应动力学

以五甲基环戊二烯基三苄氧基钛犤Cp*Ti(OBz)3犦和改性甲基铝氧烷(mMAO)为催化体系,合成了立体有规聚1-丁烯,研究了不同聚合反应温度、催化剂浓度、1-丁烯浓度下的聚合反应动力学。结果表明,在聚合反应初期,聚合速率与催化剂浓度和单体浓度的一次方成正比,求得30,40,50℃下的聚合速率常数分别为3.19×104,2.75×104,2.25×104,碰撞因子为9.31×106,表观活化能为14.3kJ/mol。     

管式反应器液相循环反应制备二甘醇乙烯基醚

以乙炔和二甘醇为原料,二甘醇钾为催化剂,采用管式反应器液相循环反应制备二甘醇乙烯基醚。研究了催化剂用量、反应温度、反应压力和停留时间等因素对乙炔转化率的影响,得到较为适宜的反应条件为：催化剂二甘醇钾用量为二甘醇质量的4%、反应温度175℃、反应压力6MPa、停留时间175s。在该条件下进行了液相连续循环反应,反应达到稳态时,二甘醇的转化率为76.03%,二甘醇单乙烯基醚收率为59.03%,二甘醇双乙烯基醚的收率为15.10%,合计二甘醇乙烯基醚总收率为74.13%。单位反应体积二甘醇乙烯基醚的产率为143.2g/（h·mL）。二甘醇与乙炔反应符合一级反应动力学方程,反应的指前因子k₀=1.20×10⁸s^–1,反应的活化能E=86.86kJ/mol。管式反应器中无气相乙炔,克服了高温高压下气相乙炔易燃易爆的危险。     

血糖预测生理模型及化工建模策略

糖尿病是一种高发病率、多并发症的内分泌代谢性疾病,目前尚不存在治愈方法,患者不仅经济负担加重,生活质量下降,病情严重者还长期面临生命威胁。近些年来,糖尿病问题日趋严重,逐渐成为社会和相关领域关注的热点之一。本文从人体血糖调节系统出发,简述了两种糖尿病的病因,并从化学工程的角度将人体类比为血糖代谢的控制系统,以此分析了糖尿病患者血糖控制的主要方式,指出了其中血糖预测的关键性作用。然后详细介绍了血糖预测生理模型的两个主要部分,即葡萄糖-胰岛素代谢模型和葡萄糖吸收模型。突出了化学工程建模策略对吸收模型构建的重要作用,并分析了该方法的优势与现有模型的不足,根据近年来的体内外研究提出了进一步的优化方案。最后,对血糖预测的未来工作进行了展望,建议深化机理研究,将血糖预测模型与化工建模策略相结合,整体理解饮食对血糖调控的作用,完善长期预测模型和个性化模型。     

An evaluation of the impact of SG1 disproportionation and the addition of styrene in NMP of methyl methacrylate

A kinetic modeling study is presented for batch nitroxide mediated polymerization (NMP) of methyl methacrylate (MMA; nitroxide: N‐tert‐butyl‐N‐[1‐diethylphosphono‐(2,2‐dimethylpropyl)] (SG1)). Arrhenius parameters for SG1 disproportionation (A = 1.4 10⁷ L mol^?1 s^?1; E_a = 23 kJ mol^?1) are reported, based on homopolymerization data accounting for unavoidable temperature variations with increasing time, that is, nonisothermicity. For low targeted chain lengths (TCLs ≤ 300), this nonisothermicity is also relevant for NMP of MMA with a small amount of styrene. Parameter tuning to copolymerization data confirms a penultimate monomer unit effect for activation (s_a2 = k_a12/k_a22=6.7; 363 K; 1: MMA; 2: styrene). To obtain, for a broad TCL range (up to 800), a dispersity well below 1.3 an initial styrene mass fraction of ca. 10% is required. An interpretation of the comonomer incorporation is performed by calculating the fractions of activation‐growth‐deactivation cycles with a given amount of monomer units and the copolymer composition distribution. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2545–2559, 2018